Air conditioning system

ABSTRACT

An air conditioning system for a vehicle passenger compartment comprises a first duct unit including at least one inlet opening and a blower device, and a second duct unit fluidly connected to the first duct unit. The second duct unit includes an evaporator and a heater core, and further includes a damper mechanism and a plurality of outlet openings. An evaporator is disposed forward of the heater core in the second duct unit and forms a part of an air-conditioning circuit. The heater core is disposed rearward of the evaporator and partially covers the second duct unit. The damper mechanism is disposed rearward of the evaporator and controls the amount of air passing through the evaporator and the heater core and introduced to the outlet openings. 
     The resulting air conditioning system is compact in size and lightweight while simultaneously providing superior air conditioning performance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to air conditioning systems, andmore particularly, air conditioning systems with improved airdistributing mechanisms for use in automotive vehicles.

2. Description of Related Art

Automotive air conditioning systems are known in the art. Generally,automotive air conditioners are provided with an air duct which has anair inlet opening and air outlet openings, and includes a heat exchangerwith a plurality of damper elements to control the temperature andpassageway of the air.

For example, U.S. Pat. No. 5,590,540 issued to Ikeda et al., whichdisclosure is incorporated herein by reference, discloses an overallconstruction of an air conditioning system.

Specifically, referring to FIGS. 1 and 2, air conditioning system 10comprises three duct units: blower unit 11; cooling unit 12; and heaterunit 13. These three duct units are fluidly connected to each other.Each of the units respectively includes the following describedcomponents. Blower unit 11 includes blower unit body 11a, blower device15 and air inlet opening 14. Air inlet opening 14 communicates with theexternal space and the automobile compartment through a re-circulatedair inlet (not shown). Cooling unit 12 includes cooling unit body 12aand evaporator 16. Evaporator 16 is enclosed within cooling unit body12a and is part of a refrigerant circuit for cooling air passingtherethrough. Heater unit 13 includes heater unit body 13a whichencloses the main air passageway through heater unit 13, heater core 17and a plurality of outlets, such as a defroster outlet 22, a footeroutlet 23 and a ventilation outlet 24, each of which opens into theautomobile compartment.

Air is drawn into blower unit 11 from air inlet opening 14, andultimately flows out into the automobile compartment through defrosteroutlet 22, footer outlet 23 and ventilation outlet 24. Normally, aircirculation is forced by blower device 15 disposed at the air inlet sideof air conditioning system 10. A first damper 25 is disposed adjacent todefroster outlet 22 and ventilation outlet 24 to control the opening andclosing of defroster outlet 22 and ventilation outlet 24. A seconddamper 26 is disposed adjacent to footer outlet 23 to control theopening and closing of footer outlet 23.

Heater core 17 of heater unit 13 is placed downstream from evaporator16, so as to divide the main passageway through heater unit 13 into twopassageways. That is, heater core 17 is placed so as to partly cover themain passageway through heater unit 13 and to form a bypass passageway31 in heater unit 13. First heater core inlet damper 20 is disposed onthe front or inlet side of heater core 17, so that it can cover the heatexchanger area of heater core 17 or close bypass passageway 31. In thismanner, bypass passageway 31, through which cooled air passes, isprovided in heater unit 13.

Air mixture chamber 30 is located at the rear or outlet side of heatercore 17 and functions as an air mixture chamber. In air mixture chamber30, the portion of air that has passed through heater core 17 and theportion of air that has passed through bypass passageway 31 may be mixedwith one another so as to control the temperature of air flowing outinto the automobile compartment through at least one of outlets 22, 23and 24.

Heater unit 13 also includes heater core damper 21 which prevents heatercore 17 from being cooled by cooled air flowing from cooling unit 12.Namely, heater core damper 21 covers the rear surface of heater core 17during the maximum cooling mode of air conditioning system 10.

In the foregoing arrangement, both the cooling unit and the heater unitrequire space. Additional space is also required where the first inletheater core damper 20 is disposed and operates. Therefore, the abilityto reduce the size and weight of the air conditioning system and make itmore compact is limited.

These and other problems with existing air conditioning systems areaddressed by embodiments of the present invention.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an airconditioning system which is compact in size and lightweight.

It is another object of the present invention to provide an airconditioning system which provides superior air conditioningperformance.

The present invention is directed to an air conditioning system and to aheater unit in that system. According to the present invention, an airconditioning system for controlling the temperature of a vehiclepassenger compartment comprises a first duct unit, or blower unit, and asecond duct unit, or heater unit. The first duct unit includes at leastone inlet opening and a blower device, such as a fan or other air movingdevice, for forcing air circulation toward an outlet opening and towardthe second duct fluidly connected to the first duct unit. The secondduct unit has a forward or upstream end and a rearward or downstream endand a main passageway therethrough. The second duct unit also includes aplurality of outlet openings disposed at the rearward or downstream endthereof An evaporator is disposed in the passageway at the upstream orforward end of the second duct unit and forms a part of anair-conditioning circuit. A heater core is disposed rearward ordownstream of said evaporator in the passageway and partially covers thepassageway of the second duct unit. A damper mechanism is disposedrearward of the evaporator to control the amount of air passing throughthe evaporator and heater core and introduced to one or more of theplurality of outlet openings. Specifically, a first damper is preferablydisposed rearward of the evaporator for controlling a first amount ofair passing through the evaporator and flowing out of one or more of theplurality of outlet openings. A second damper is preferably disposedrearward of the heater core for controlling a second amount of airflowing to one or more of the plurality of the outlet openings.

Further objects, features and other aspects of this invention will beunderstood from the following detailed description of the preferredembodiments of this invention with reference to the attached drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic vertical sectional view of a conventional airconditioner system in accordance with the prior art.

FIG. 2 is a schematic perspective view of a heater unit of aconventional air conditioner system in accordance with the prior art.

FIG. 3 is a schematic vertical sectional view of an air conditionersystem in accordance with a first embodiment of the present invention.

FIG. 4 is a schematic perspective view of a heater unit of an airconditioner system in accordance with the first embodiment of thepresent invention.

FIG. 5 is a partial schematic vertical sectional view of a heater unitof an air conditioner system in accordance with the first embodiment ofthe present invention.

FIG. 6 is a schematic vertical sectional view of an air conditionersystem in accordance with a second embodiment of the present invention.

FIG. 7 is a schematic perspective view of a heater unit of an airconditioner system in accordance with the second embodiment of thepresent invention.

FIG. 8 is a partial schematic vertical sectional view of a heater unitof an air conditioner system in accordance with the second embodiment ofthe present invention.

FIG. 9 is a schematic perspective view of an evaporator of an airconditioner system in accordance with a third embodiment of the presentinvention.

FIG. 10 is a partial schematic vertical sectional view of a heater unitof an air conditioner system in accordance with the third embodiment ofthe present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 3, 4 and 5 depict an automotive air conditioning system inaccordance with a first embodiment of the present invention. The airconditioning system is provided with air duct units having air inletopenings, air outlet openings, heat exchangers and a plurality of damperelements for controlling the temperature and passageway of the air. InFIGS. 3-10, like reference numerals are used to denote elementscorresponding to those shown in FIGS. 1-2, so that further explanationthereof is omitted.

Air conditioning system 100 includes a first duct unit or blower unit 11and a second duct unit or heater unit 13. Blower unit 11 has at leastone inlet opening and at least one outlet opening and includes a blowerdevice 15 for forcing air circulation toward its outlet opening andtoward heater unit 13. Heater unit 13 has a forward or upstream end anda rearward or downstream end. Heater unit 13 is fluidly connected at itsupstream end to blower unit 11. Heater unit 13 includes heater unit body13a, a main passageway enclosed thereby, evaporator 116, heater core 17,a plurality of dampers 120, 21 and 127, and a plurality of outlets atthe downstream end, such as a defroster outlet 22, footer outlet 23 andventilation outlet 24. These outlets all open into the vehiclecompartment. Heater core 17 is disposed in the main passageway of heaterunit 13, so as to partially cover the main passageway, and form bypasspassageway 31. Air mixture chamber 30 is located downstream from heatercore 17 and bypass passageway 31.

Evaporator 116 is disposed in the main passageway at the upstream end ofheater unit 13, downstream from blower unit 11 and upstream from heatercore 17. Evaporator 116 includes upper and lower tanks 116a and 116b,and a plurality of tubes 116c, which are preferably cylindrical,arranged therebetween. Upper and lower tanks 116a and 116b arevertically opposite to each other with a space left in between them.Each of tubes 116c extends vertically and is connected to upper andlower tanks 116a and 116b.

Further, evaporator 116 has substantially a triangular cross sectionwhen viewed horizontally or in the direction perpendicular or transverseto tubes 116c. Further, evaporator 116 includes an air intake surface116d, a first air exhaust surface 116e and a second air exhaust surface116f, each of which are formed parallel to tubes 116c.

Air intake surface 116d faces toward the open outlet end of blower unit11 so as to suction or draw in air flow from blower device 15. First airexhaust surface 116e faces the front of the heat exchanger area ofheater core 17 so that a first portion of air flow may discharge or flowout to heater core 17. Second air exhaust surface 116f faces towardbypass passageway 31 so that a second portion of air flow, such ascooled air, may flow or be discharged downstream of heater core 17directly to the outlet openings without passing through heater core 17.

Furthermore, first evaporator damper 120 is disposed on the second airexhaust surface 116f. The amount of air flow flowing into bypasspassageway 31 is controlled by regulating the opening of firstevaporator damper 120. A second evaporator damper 127 is disposeddownstream from evaporator 116 and upstream of heater core 17. Thesecond evaporator damper 127 comprises a plate member which coversapproximately half of the area of first air exhaust surface 116e when itcloses, in order to partially shut off the cooled air flowing out toheater core 17. Heater core damper 21 is disposed on the rear heatexchanger area of heater core 17 in order to intercept cooled air whichhas passed through second exhaust surface 116f of evaporator 116.

Referring to FIG. 5, the plurality of tubes 116c of evaporator 116 arearranged so that adjacent rows are zigzag or offset from each other. Inother words, the plurality of tubes 116c are arranged such that theportion of the air flow flowing substantially perpendicular to secondair exhaust surface 116f strikes at least one of the tubes 116c, and theportion of the air flow flowing substantially perpendicular to first airexhaust surface 116e passes through evaporator 116 without striking thetubes 116c.

As a result, a plurality of air straight air paths "A" are formed in thedirection perpendicular to first air exhaust surface 116e, and aplurality of zigzag air paths "B" are formed in the directionperpendicular to second air exhaust surface 116f.

In this configuration, the air flow which is blown from blower device 15of blower unit 11, flows into the interior of evaporator 116 through airintake surface 116d. It should be noted that evaporator 116, which mayalso be called a multitubular heat exchanger, has a structure such thatany air stream between the upper and lower tanks is substantially freefrom any constraint and air may be substantially freely changedtherebetween.

The air conditioning system 100 operates as follows. All of the airpassing through evaporator 116 flows toward and passes through heatercore 17 when first evaporator damper 120 is closed and heater coredamper 21 and second evaporator damper 127 are opened, i.e., during"maximum heat mode".

All of the air passing through evaporator 116 flows toward bypasspassageway 31 without passing through heater core 17 when firstevaporator damper 120 is opened, and heater core damper 21 and secondevaporator damper 127 are closed, i.e., during "maximum cooling mode".

Furthermore, the portion of air passing through heater core 17 and theportion of air passing through bypass passageway 31 are mixed with oneanother in air mixture chamber 30 when heater core damper 21 and secondevaporator damper 127 are opened and first evaporator damper 120 ispartially opened by regulating its opening i.e., during "air mixingmode".

Air conditioning system 100 may also be operated in several operationmodes, such as "ventilation mode", "bi-level mode", "foot mode","foot/defrost mode" and "defrost mode", by regulating first and seconddampers 25 and 26 in response to the demand of the passenger in thevehicle.

As a result, the air conditioning system may be as easily operated inthe respective operation modes as in existing systems.

In this configuration, evaporator 116 is contained in the mainpassageway of heater unit 13, i.e., in the space which is occupied byfirst heater core inlet damper 20 in the system depicted in FIGS. 1 and2.

Accordingly, the configuration of this embodiment is more compact andreduced in size and weight than existing systems. Simultaneously, theair conditioning system of the present invention is easily controlledwith respect to the different operation modes. In other words, the airconditioning system does not need a cooling unit 12 as required inexisting systems.

The arrangement of tubes 116c in evaporator 116 also reduces airpressure loss. Such loss may occur as air passes between the pluralityof tubes when air flows from evaporator 116 toward heater core 17.

FIGS. 6, 7 and 8 depict a second embodiment of the present invention.This embodiment is directed to a modified configuration of airconditioning system 100 of the first embodiment.

In this embodiment, evaporator 216 includes upper and lower tanks 216aand 216b, and a plurality of tubes 216c, which are preferablycylindrical, arranged therebetween similar to the configuration of thefirst embodiment. Evaporator 216 forms substantially a quadrilateral inthe cross section which is horizontal or lies perpendicular ortransverse to the row of tubes 216c. Further, evaporator 216 includes anair intake surface 216d, a first air exhaust surface 216e, a second airexhaust surface 216f and third air exhaust surface 216g, each of whichare formed parallel to tubes 216c.

Heater unit 13 further includes a cooling bypass passageway 132 formedon the side opposite from and apart from heater core 17. Cooling bypasspassageway 132 has a first open end 132a facing toward third air exhaustsurface 216g of evaporator 216 and a second open end fluidly connectedto ventilation outlet 124.

Thereby, cooling bypass passageway 132 substantially acts to convey thecooled air "C", which is cooled through evaporator 216, directly toventilation outlet 124 without mixing with the heated air heated byheater core 17, when in the bi-level mode.

Accordingly, this configuration has a desirable and ideal bi-level modewhile simultaneously having the same advantages as those in the firstembodiment.

FIGS. 9 and 10 depict a third embodiment of the present invention. Theembodiment is directed to a modified configuration of the airconditioning system of the second embodiment.

As depicted in FIGS. 9 and 10, this embodiment has an area "α" in therow of tubes 216c adjacent to first open and 132a of cooling bypasspassageway 132. This area is arranged differently from the other area ofthe row of tubes. Namely, tubes 216c in area "α" are arranged such thatthe portion of air flow "D", flowing in evaporator 216 and to a surfaceslightly inclined with respect to second air exhaust surface 216f,strikes at least one tube 216c. Tubes 216c are aligned in rows the sameas the alignment of the second embodiment of the present inventionexcept in the area "α".

First evaporator damper 120 is controlled by placing it at the anglecreated between second air exhaust surface 216f of evaporator 216 andthe inner wall of cooling bypass passageway 132 of heater unit 13.Namely, first evaporator damper 120 guides the portion of air passedthrough area "α" to advance in a direction which is oblique to first airexhaust surface 216e as shown in FIGS. 9 and 10.

As a result, the heat exchange from tubes 216c is more efficient as theair passes through the different areas of evaporator 216.

In this third arrangement, substantially the same advantages as those inthe first and second embodiments can be obtained. Furthermore, thisembodiment increases the heat-exchange efficiency of evaporator 216 evenmore.

Although the present invention has been described in connection with thepreferred embodiments, the invention is not limited thereto. It will beeasily understood by those of ordinary skill in the art that variationsand modifications can be easily made within the scope of this inventionas defined by the following claims.

I claim:
 1. An air conditioning system for controlling the temperatureof a vehicle passenger compartment, said air conditioning systemcomprising:a first duct unit including a blower device; and a secondduct unit fluidly connected to said first duct unit, said blower deviceforcing air circulation from said first duct unit toward said secondduct unit, said second duct unit comprising:a forward end and a rearwardend; a passageway therethrough; a plurality of outlet openings disposedat the rearward end thereof; an evaporator disposed in said passagewayat the forward end of the second duct unit, said evaporator comprisingan exhaust surface and forming a part of an air-conditioning circuit; aheater core disposed in said passageway of said second duct unitrearward of said evaporator and partially covering said passageway ofsaid second duct unit; and a damper mechanism disposed rearward of saidevaporator so as to control an amount of air passing through saidevaporator and said heater core and introduced to one or more of saidplurality of outlet openings, said mechanism comprising a first damper120, said first damper having a closed position whereby all air flowpasses through said heater core solely by placing said first damper insaid closed position, a second damper 21, said second damper having aclosed position whereby all air flow through said heater core isprevented solely by placing said second damper in said closed position,and a third damper 127, said third damper having a closed positionwhereby said third damper covers a portion of said exhaust surface ofsaid evaporator to partially shut off air flowing to said heater corewhen said third damper is in said closed position.
 2. The airconditioning system of claim 1, wherein said first damper is disposedrearward of said evaporator for controlling a first amount of airflowing to said one or more of said plurality of outlet openings andsaid second damper is disposed rearward of said heater core forcontrolling a second amount of air flowing through said heater core tosaid one or more of said plurality of outlet openings.
 3. The airconditioning system of claim 1, wherein said evaporator includes anupper tank and a lower tank, and a plurality of tubes fluidly connectedto said upper and lower tanks.
 4. The air conditioning system of claim1, wherein said second duct unit further includes a cooling bypasspassageway formed apart from said heater core for directly introducingan air flow passed through said evaporator to at least one of saidplurality of outlet openings.
 5. The air conditioning system of claim 1wherein said plurality of outlet openings comprise an upper outletopening, a defrost outlet opening and a lower outlet opening.
 6. An airconditioning system for controlling the temperature of a vehiclepassenger compartment, said air conditioning system comprising:a firstduct unit including a blower device; and a second duct unit fluidlyconnected to said first duct unit, said blower device forcing aircirculation from said first duct unit toward said second duct unit, saidsecond duct unit comprising: a forward end and a rearward end; apassageway therethrough; a plurality of outlet openings disposed at therearward end thereof; an evaporator disposed in said passageway at theforward end of the second duct unit, said evaporator forming a part ofan air-conditioning circuit; a heater core disposed in said passagewayof said second duct unit rearward of said evaporator and partiallycovering said passageway of said second duct unit; and a dampermechanism disposed rearward of said evaporator so as to control anamount of air passing through said evaporator and said heater core andintroduced to one or more of said plurality of outlet openings, whereinsaid evaporator includes an upper tank, a lower tank, and a plurality oftubes fluidly connected to said upper and lower tanks, and wherein saidevaporator further includes an intake surface for sectioning an airflow, a first exhaust surface for discharging first portion of said airflow toward said heater core and a second exhaust surface fordischarging a second portion of said air flow to said one or more ofsaid plurality of outlet openings by bypassing said heater core.
 7. Theair conditioning system of claim 6, wherein said plurality of tubes arealigned in a row so that at least a portion of said air flow which issubstantially perpendicular to said first exhaust surface passes throughsaid evaporator without striking any of said tubes.
 8. The airconditioning system of claim 6, wherein a part of said plurality oftubes are aligned in a row so that at least a portion of said air flowin said evaporator which is oblique to said first exhaust surfacestrikes at least one of said tubes.
 9. A heater unit for airconditioning system, said system including a blower unit fluidlyconnected to said heater unit, said blower unit having blower device forforcing air circulation toward said heater unit, said heater unitcomprising:an upstream end and a downstream end; a body having apassageway therethrough; a plurality of outlet openings disposed at thedownstream end thereof; an evaporator disposed in the passageway at theupstream end, said evaporator comprising an exhaust surface; a heatercore disposed downstream from said evaporator so as to partially coverthe passageway through said heater unit; and a damper mechanism disposeddownstream from said evaporator so as to control an amount of airpassing through said evaporator and said heater core and introduced toone or more of said plurality of outlet openings, said mechanismcomprising a first damper, said first damper having a closed positionwhereby all air flow passes through said heater core solely by placingsaid first damper in said closed position, a second damper, said seconddamper having a closed position whereby all air flow through said heatercore is prevented solely by placing said second damper in said closedposition, and a third damper, said third damper having a closed positionwhereby said third damper covers a portion of said exhaust surface ofsaid evaporator to partially shut off air flowing to said heater corewhen said third damper is in said closed position.
 10. The heater unitof claim 9, wherein said heater unit further includes a bypasspassageway formed in said heater unit for bypassing said heater core,and a mixture chamber disposed downstream from said heater core and saidbypass passageway.
 11. The heater unit of claim 10, wherein said firstdamper is disposed downstream from said evaporator for controlling afirst amount of air flowing out said bypass passageway and said heatercore into said mixture chamber, and said second damper is disposeddownstream from said heater core for controlling a second amount of airflowing through said heater core into said mixture chamber.
 12. Theheater unit of claim 9, wherein said evaporator includes an upper tank,a lower tank and a plurality of tubes fluidly connected to said upperand lower tanks.
 13. The heater unit of claim 9, wherein said heaterunit further includes a cooling bypass passageway formed apart from saidheater core for directly introducing an air flow passed through saidevaporator to at least one of said plurality of outlet openings.
 14. Theheater unit of claim 9, wherein said plurality of outlet openingscomprise an upper outlet opening, a defrost outlet opening and a loweroutlet opening.
 15. A heater unit for air conditioning system, saidsystem including a blower unit fluidly connected to said heater unit,said blower unit having blower device for forcing air circulation towardsaid heater unit, said heater unit comprising:an upstream end and adownstream end; a body having a passageway therethrough; a plurality ofoutlet openings disposed at the downstream end thereof; an evaporatordisposed in the passageway at the upstream end; a heater core disposeddownstream from said evaporator so as to partially cover the passagewaythrough said heater unit; and a damper mechanism disposed downstreamfrom said evaporator so as to control an amount of air passing throughsaid evaporator and said heater core and introduced to one or more ofsaid plurality of outlet openings, wherein said evaporator includes anupper tank, a lower tank and a plurality of tubes fluidly connected tosaid upper and lower tanks, and wherein said evaporator further includesan intake surface for sectioning an air flow, a first exhaust surfacefor discharging a first portion of said air flow toward said heater coreand a second exhaust surface for discharging a second portion of saidair flow to said one or more of said plurality of outlet openings bybypassing said heater core.
 16. The heater unit of claim 15, whereinsaid plurality of tubes are aligned in a row so that at least a portionof the air flow which is substantially perpendicular to said firstexhaust surface passes through said evaporator without striking any ofsaid tubes.
 17. The heater unit of claim 16, wherein a part of saidplurality of tubes are aligned in a row so that at least a portion ofthe air flow in said evaporator which is oblique to said first exhaustsurface of said evaporator strikes at least one of said tubes.